Internal-combustion engine



Dm 21,1946. y

R. DAUB INTERNAL-COMBUSTION ENGINE Filed Nov. 20. 1944 lll Uf i if IN V EN TOR.

Patented Dec. 24,1946

UNirEo srA'ras PATENr orifice Y 2,412,952 mrERNAL-oormosrron monza Itudolph Danb, West Caldwell, N. J; Application November zo, 1944, serial No. 564,191

4 Claims. i

This invention relates to internal combustion engines of the two-cycle type, and particularly to such engines having opposed cylinders where two crank shafts are placed in opposite ends of the cylinder block and crank case.

In such engines one crank shaft operates a piston controlling the intake ports while the piston attached to the other shaft controls the exhaust ports of the same cilinder. The pistons are moving in opposite directions-with their positions phased in such a manner as toeiect an early opening and closing of theexhaust ports in comparison with the intake ports.

The object of the invention. is to provide increased power w. lin the overall dimensions oi the engine.

Further objects of the invention, particularly in the employment of a minimum number of fuel injectors or nozzles and the attainment of better cooling and scavenging will appear from the following speciilcation taken in connection with the accompanying drawing showing a central sectional view of a typical engine structure.

In the engine shown in the drawing a combined cylinder block and crank case housing l has the centers of the two crank shafts at and i2 with crank pins i3, I 4. Operably 'connected to crank pin I3 is master rod l5. and articulated rod IB is hinged to master rod |5 by means of the fulcrum pin l.

Master rod |5 is attached to piston I8 by pis- The combustion chamber 3| is formed in the main between the heads of pistons 23, 28, this being spaced to give a comparatively wide gap 35 at nearest approach while pistons I8, l1 and cylinder 22 at the same time form a very narrow gap 35 between their head faces at the time of injection of the fuel spray by the nozzle tip 30. This violently squeezes the air out from between the faces of pistons i8, 2l and projects it turbulently through the throat 36 into the gap 3G between the pistons 23, 28, and in a direction oppOsite to the oncoming fuel spray. 'I'his causes an intimate and prompt mixing of fuel and air, good atomization and ecient combustion since the velocity of the air. through the throat and the intensity of the turbulence reaches its maX- imum at about the time 0f the injection, i. e., the innermost positions of pistons I8, 27. The result is a very thorough burning of the fuel.

'Ihe shape of the throat and its location between the gap 35 and combustion chamber 3| may also be such as to cause a rotational whirl of the air charge in combustion chamber 3| around the axis of the cylinder 25. The formal tion of the piston heads lat both the narrow gap ton pin i9, the edge 20 of piston I8 controlling v the opening and closing of the intake ports 2| of the cylinder 22. Attached to articulated rod I6 is the corresponding articulated piston 23 having its edge 2t controlling the intake ports 2| of cylinder 25.

The exhaust ports 26 of the cylinders 22, 25 are controlled by the other set of pistons 21, 28 connected to crank pin It by master connecting rod -I 5a, articulated rod |6a and piston pins |9a. The geometry of piston motions, side pressures and the effect of the relative phasing of the pistons are set forth in my copending application Serial No. 510,717.

Positioned in the cyllinder block |0 is the injection nozzle 29, the inner tip 30 of which protrudes into the combustion chamber 3|. Cam shaft 32 by means of rocker 33 operates the nozzle 29 to inject the fuel jet at proper time intervals. Cam shaft 32 is rotated at crank shaft speed by gears (not shown). Water jacketing y' is provided around al1 of the cylinders, the engine usually comprising a longitudinal series of 35 and the wider gap 34 may be such as to give any desired whirl, the throat outline and location being correspondingly arranged for cooperation if desired. Similarly the number of injectors and their positioning may be varied to cooperate in creating the whirl.

The intake 2| and exhaust 26 are formed as a belt of orifices surrounding the cylinders and communicating with each other so as to provide for continuous distribution and passage of the gases into and out of the cylinders, suitable manifolds being provided at the outside of the engine.

Hitherto diiliculty has been experienced in opposed cylinder engines in eiectively cooling the exhaust piston because the outer edge of the piston top is subjected to the scorching eiect of the exhaust flames passing at high velocity between said edges and the edges of the exhaust ports in the cylinders. While the latter can be cooled by water, heat dissipation from the piston edge and l piston top and piston rings must be provided by heavy sections of the piston or by oil cooling, or both, if reasonably. high output is to be satisfactorily sustained. The larger the bore of the engine the more this overheating is aggravated, and. in fact, this limits the size in.output per cylinder in present opposed two-cycle engines of this type. In the engine of this invention, the speciiic power output per cylinder unit is increased by keeping the diameters of the pistons relatively small due to the division of the power between the two pistons for a given piston top area. This increases the combined piston circumference by 41% as compared to a single piston of similar area, thereby increasing the heat-dissipating area f circumference multiplied by piston skirt length) by the same amount.

The use of two pistons instead of one, increasing the circumference 41%, permits the equivalent enlargement in inlet and exhaust port areas resulting in better scavenging and low pump losses, better fuel economy and attaining a more eilicient and more economical power plant.

In current engines of the opposed type, two, two, three or four injection nozzles are used per cylinder unit because the combustion chamber is of the quiescent type with little turbulence and a rather flat shape, depending upon atomization to produce distribution of thefuel. In the present engine, the distribution does not so depend upon atomization but is achieved rather by the highly turbulent air projected towarda single nozzle to meet the merging fuel spray head on. The shape of the chamber is also very advantageous, being formed by the combined strokes of two sets of pistons, four in all. In addition to these advantages the engine is shorter and more compact, permitting a lighter and safer structure with less tendency toward torsional deflection of the shafting. The engine is thus improved in operation and at the same time reduced in cost and made more durable in service, and it is apparent that various changes in the details of the construction may be made preserving these advantages and within the scope of the invention.

I claim:

1. An internal combustion engine comprising parallel crank shafts operating at the same speed and each having a crank pin, parallel cylinders between said crank shafts, a combustion chamber midway between the ends of said cylinders, and

two sets of oppositelymoving pistons in said cylinders, one set being connected to one crank shaft and the other set to the other crank shaft. intake passages connecting said cylinders and controlled by one set of pistons and exhaust passages connecting said cylinders and controlled by' the other set of pistons.

2; In an internal combustion engine a pair of -parallel crank shafts having a series or crank pins, a pair of pistons connected to each crank pin, parallel cylinders containing said pistons between said crank shafts, a passage connecting each pair of cylinders midway between their ends and forming with the heads of the corresponding pistons a central combustion space, and intake and exhaust passages connecting said cylinders.

3. In an internal combustion engine a pair of parallel crank shafts having a series of crank pins, a pair of pistons connected to each crank pin, parallel cylinders containing said pistons between said crank shafts, a passage connecting each pair of cylinders midway between their ends and forming with the heads of the corresponding pistons a central combustion space, and intake and exhaust passages connecting said cylinders, said passages and pistons on one side of the engine being further from the center than on the other side of the engine.

4. A two cycle internal combustion engine comprising parallel crank shaftsoperating at the same speed, master and auxiliary connecting rods for said shafts, parallel cylinders between said crank shafts, 'pairs of oppositely moving pistons in said cylinders journaled to said connecting rods, a combustion chamber for said pairs of pistons midway between the ends of said cylinders, intake passages connecting the cylinders for one of said crank shafts and controlled by the corresponding pistons of said cylinders, and exhaust passages connecting the cylinders of the other crank shaft and controlled by the corresponding pistons thereof.

RUDOLPH DAUB. 

